Use and application of damp-proof renders/plasters

The Weber damp-proof renders/plasters (all in accordance with the guidelines of WTA - Scientific and Technical Working Group for Building Conservation and Monument Preservation, Germany) are used indoors and outdoors in one or two layers up to 40 mm, depending upon roughness and salt content of masonry. Thanks to their large pore structure, the damp-proof renders/plasters are able to take over crystal-building salts and store them within their porous body. The removal of damaged renders/plasters at a distance of 80 cm above the visibly damaged area with moisture and salt contamination is the main condition for substrate preparation. When used as internal waterproofing layers, damp-proof plasters as "dampness regulating plasters" uptake the condensation moisture within the rooms for a certain period of time.

Simple & safe to the goal

  1. 1. The evaluation of moisture and salt content of masonries as well as knowledge of building uses are pre-requisite for professional restoration and the associated rebuild of the walls is a detailed examination of the surfaces, the salt and moisture content and the local conditions.

  2. 2. Moist or damp renders/plasters must be removed by mechanical means.

  3. 3. Scrape out the damaged and salt-loaded joint mortar network at a depth of at least 2 cm.

  4. 4. Prepared wall surface.

  5. 5. The quick-setting stipple coat weber.san 951 S provides a bonding with the substrate. It is applied net-like (i.e. with a surface coverage of 50%), using the throw-on technique with a triangular hawk trowel. If a waterproofing slurry is applied on the internal side of the basement wall, the coverage of the stipple coat must be 100%.

  6. 6. Application of the damp-proof render/plaster weber.san 954, using a flat trowel.

  7. 7. For the application of the damp-proof render/plaster by machine (for ex. mono fu of the company M-tec) we recommend a screw jacket D 6-3 and a supplementary mixer.

  8. 8. In case of 2-layer application comb the first layer horizontally immediately with the flat trowel weber.sys Aufstreichkelle + triangular notch blade Zahnleiste no. 2 (notch size 5 mm) before applying the second layer.

  9. 9. Rule level the damp-proof render/plaster with an aluminium beam.

  10. 10. Smooth the surface of weber.san 954 with a sponge board (red).

  11. 11. Whenever damp-proof renders/plasters are applied as cement-based waterproofing slurries, one layer is in general sufficient. Insert the woven glass fiber mesh for damp-proof renders weber.sys 987 into the upper third of the render layer. The render takes over the task of moisture regulation, i.e temporary uptake of condensate moisture.


    12. Measures in accordance with the salt content of masonry substrate.

Find all our products near you in more than 2000 outlets